1. Field of the Invention
The invention relates to an abnormality detection device and an abnormality detection method that detect the abnormality of an engine control device mounted on a vehicle. Specifically, the invention relates to an abnormality detection device and an abnormality detection method that detect the abnormality in which a torque more excessive than a torque intended to be output by a driver is output.
2. Description of Related Art
FIG. 1 of Japanese Patent Application Publication No. 2010-190196 (JP 2010-190196 A) discloses an engine control device that performs torque control of an engine. In this engine control device, an increased air amount (corresponds to a target load factor) is calculated from a target torque and a target efficiency using operation elements 341 and 343, the conversion from the increased air amount to a throttle opening is performed, and the control amount of the throttle opening is thereby set. In addition, in this engine control device, the target ignition timing of the engine is calculated from the target efficiency, and the ignition timing of the engine is thereby controlled.
In the engine control device of JP 2010-190196 A, in order to monitor whether or not the torque more excessive than the torque intended to be generated by a driver is generated, it is necessary to monitor whether or not the operation elements 341 and 343 normally operate. That is, it is necessary to monitor whether or not three values of the target torque, the target efficiency, and the increased air amount (the target load factor) are in the normal relationship.
As a technology for performing this monitoring, there is proposed a method in which a target torque for monitoring is calculated by using the target efficiency and the increased air amount, a torque deviation between the target torque for monitoring and the target torque is determined, a count number is incremented when the torque deviation exceeds a threshold value, and it is determined that an abnormality is present, i.e., the torque more excessive than the torque intended to be generated by the driver is generated when the count number exceeds a threshold value (this technology is referred to as a proposed technology).
In the engine control device of JP 2010-190196 A, when the target efficiency is unusually decreased from one times its normal value to 0.1 times the normal value, the increased air amount is increased, the control amount of the throttle opening is increased, and the excessive torque is output. The target ignition timing is retarded in order to prevent the excessive torque. On the other hand, the retard angle limit of the target ignition timing is typically set to a misfire limit (e.g., −20°). Consequently, the target ignition timing cannot be retarded to the retard angle (e.g., −40°) for preventing the excessive torque. As a result, the excessive torque is output.